Variable pitch propeller



Jan. 2, 1934. H. c. ROTH VARIABLE FITCH PROPELLER Filed June 30, 1932 2 Sheets-Sheet 2 r I1-v VEfoR.

BY a al TTORNEYS Patented Jan. 2, 1934" UNITED sTA rss terrein*A VARIABLE Piron rRoPELLEa Harris o. Roth, south Bend, Ina., assignor, by

mesne assignments, to Eclipse Aviation Corporation, East Orange,-N. Jersey J., a corporation of New Application June 30, 1932. Serial No. 620,260 y 19 claims. (Chivo-4163) [,/in which the pitch of the-blades is both increasedand decreased by a single operating mechanism movable in one-direction only.

A further object is to provide a variable pitch propeller structure wherein the pitch of the blades is manually controllable in a novelmanner and wherein the operator is at all times informed as to the pitch of the blades.

Other objects and advantagesv of the invention will appear more fully from the following detailed description taken in connection with the accompanying drawings showing one embodiment of the invention. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not to be Y taken as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings wherein like reference numeralsl indicate, like parts throughout the several views:

Fig. 1 is a side elevation partly in section of au propeller embodying thepresent invention;

Fig. 2 is a section online 2 2 of Fig. 1 with parts broken away;

Fig. 3 is a longitudinal section taken angles to Fig. 1; and

Fig'. 4 is a section on line 4-4 of Fig. 3 .with parts shown in elevation.

Referring more particularly to the drawings, the propeller shown therein is constituted by a driving shaft 5 having a hub 6 secured thereto in any suitable manner, the hub yhaving sockets 7in which blades 8 are mounted so as to be' rotatable about their longitudinal axes. An endless at right cam .9 of suitable contour having anges V10 is It will be appreciated that the friction between the cam and hub is suflicient to normally prevent rotation of the blades in their sockets except when the cani is intentionally rotated relatively to the hub by mechanism tov be hereinafter described.

YMeans are provided for securing the blades in the hub so as to be freely rotatable therein. As shown, such means are constituted by split sleeves 12 surrounding the -root end of each of the blades and having shoulders 13 therein adapted to 'engage corresponding shoulders formed on the root ends of the blades, suitable clamping rings 14 being provided to maintain the sleeves and blades in assembled relation. Each of the sleeves 12 has an external shoulder' 15 adapted to provide one seat for a thrust bearing 16 of any suitable type, the other seat therefor being provided by an annular member l17 adapted to be screw threaded or /ot/herwise suitably secured in the socket 7. The bearings 16 are preferably packed Wi h lubricant and a suitable packing ring 18 and packing 19 are provided cooperating with the'ring 17 and sleeve 12 to preventthe lubricant from being thrown out by centrifugal force during rotation of' the propeller. A second bearing 20 "is provided between the socket 7 and sleeve 12 to maintain the blades in alignment with the sockets while permitting freerotation thereof. The inner end of each sleeve 12 is provided with a pair of projecting lugs 21 adapted to str'addle one of the links ll to operatively connect the links with the blades.

Means are provided under the control of an operator to effect relative rotation between the cam and hub,`- in order to obtain a variationl in the pitch of the blades. As shown, such'. means are constituted by a brake drum 22, Figs. 1 and 2, rotatably carried by the hub 6 and heldthereoh by a ring 23, brake shoes 24 Apivoted at 25 to a stationary member 26) cooperating/*therewith for a purpose which will appear more fully hereinaften `A pairy of oppositly disposed sleeve meml bers 27 are rigidly secure/d to the brake drums'22 and project through(/elongatedv slots 28 in thehub, each of the/sleeve members 27 carrying spring 'pressedfpawls 29 engaging ratchet teeth 30 on the cam 9. Springs 3l areprovided between A the sleeves 27 and the hub tending to move the sleeves and brake .drum in such a direction relative to the hub that the pawls 29 will overrun the ratchet teeth 30, movement of the sleeve in/ response to springs 31 being limited by the en of slot 28 as will be apparent from Fig. 1.

In order to operate the brake shoes 24 to engage the drum 22, a suitable cam 32 is provided between the free ends of the shoes, the cam being rotatably mounted on the stationary part 26 and adapted to be rotated by a lever 33 which is con- Y nected to an arm 34 on the cam by any suitable connection such, for example, as a Bowden wire v35. The lever 33 is pivoted upon a stationary member 36 on the machine with which the propeller is used and an indicating disc 37 is also rotatably mounted on said member 36, the indicating disc bearing suitable indicia which, inv

conjunction with a stationary reference mark 38, informs an operator of the existing pitch of the propeller blades. The disc 37 carriesa ratchet Wheel 39 rigidly attached thereto and a pawl 40 pivotally mounted on the lever 33 cooperates therewith to turn the disc 37 when the lever 33 is moved to apply the brake, a stop 41 being provided to limit movement of lever 33 in the brake releasing direction. A second pawl 42 is' pivotally mounted on a stationary part and cooperates with the ratchet wheel 39 to prevent the same from turning with lever 33 when it is moved in a direction to release the brake. From the above, it will be apparent that each time the lever 33 is moved to apply the brake, the ratchet Wheel 39 will be rotated one tooth and the disc 3'7 will be rotated until the next adjacent indicium carried thereby is brought opposite the reference mark 38.

In operating the above described propeller, the operator, when it is desired to change'the pitch of the propeller blades, moves the lever 33 to the right in Fig. 1 to rotate cam 32 to spread brake shoes 24 into engagement with the brake drum 22 thereby holding the brake drum against rotation. Since the pawls 29 which engage ratchet teeth 30 are carried by the brake drum 22, the pawls and consequently the ratchet teeth and cam 9 will be held stationary, but since the hub continues rotating, the cam will be rotated relatively to the hub to move arms- 11' about their pivotal mountings, the intermediate portions of the said arms cooperating with they lugs 21 on each blade to thereby change'the pitch of the blades. After the hub has rotated a certain amount relatively to the cam, sleeves 27 are engaged bythe upper ends of slots 28, as viewed in Fig. 1, and the sleeves and consequently the brake drum, pawls and cam are then rotated with the hub slipping the brake drum on the brake shoes. Thus it will be apparent that the length of the slots 28 predetermines the amount of relative rotation between the cam 9 and the hub vand consequently the amount which the pitch of the blades can be varied with each operation `of the brake. When the lever 33 is moved back against the pin 4l, the brake is released and the springs 31 are effective to move sleeves 27 back against the other ends of slots 28, pawls 29 overrunning ratchet teeth 3() and accordingly effecting no movement of cam 9. It will be apparent that each brake applying movement of the lever 33 moves the indicator 37 an amount corresponding to the amount the piteh'of the blades is changed by each operation of the brake mechanism and that accordingly the indicator at all times accurately informs the operator of the actual pitch of the propeller blades. It will also be apparent that any desired pitch within the limits set ,byY the design of the cam can be obtained by operat ing the pitch-changing mechanism the proper number of times, the pitch of the blades being increased as the cam moves links 11 in one direction and decreased as it moves them in the opposite direction.

Thus, there is provided by the present invention a novel variable pitch propeller in which the pitch of 'the blades may be both increased and decreased in predetermined increments by a single operating mechanism which is movable in one direction only, the power for moving the blades being furnished by the driving shaft. The provision of the indicating disc associated With the operating lever results in an extremely simple and "reliable means for informing the operator as tothe pitch of the blades and moreover enables him to maintain the pitch at the valuef which will yield maximum propeller efficiency under existing conditions.

While there has been shown and described only one embodiment of the present invention, it will be understood that 'the sameis not limited thereto but is capable of being embodied in various mechanical forms. Thus, brake operating mechanism other than that shown might be employed or other changes occurring to one skilled in the art might be made without departing from the spirit and scope of the invention. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. `A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, and pitch-changing means associated withsaid blades including a control member movable in one direction only for both increasing and decreasing the pitch of the blades, said' member being positioned exteriorly of said propeller.

2. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, a member having an inclined surface carried by said hub, means for operatively connecting said blades and said mem- `ber, and means for moving said member in one direction only to both increase and decrease'the pitch of the blades.

3. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by the hub, an endless lcam carried by said hub and rotatabletherewith, means for operatively connecting the blades and the cam, and means for moving said cam relatively to said hub to increase or decrease the pitch of the blades.

4. A propeller comprising a driving shaft, a hub on said shaft, a plurality off blades rotatably carried by said hub, an endless cam carried by said hub, means for operatively connecting said blades and said cam, and means operated by the power of said driving shaft for moving said cam relatively to said hub to increase or decrease the pitch of the blades.

5. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, an endless cam carried by and rotatable with said hub, means for operatively connectingthe cam and blades, and means for moving the cam relative to the hub in predetermined increments for changing the pitch of the blades.

6. A propeller comprising a driving shaft,.a hub on said shaft, a plurality of blades rotatably carried by said hub, an endless cam carried by said hub, means for operatively connecting said cam and blades, and means operated by the power of said driving shaft for moving the cam in predetermined increments for changing the pitch of the-blades.

7. A propeller comprising -a driving shaft, a hub on said shaft, a plurality of blades carried by said hub, an endless cam carried by said hub, means for operatively connecting the cam and blades whereby the pitch of the blades will be changed when the cam is rotated relatively to the hub, and means for retarding rotation of the cam while said hub continues rotating to effect relative rotation therebetween.

8. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades carried by said hub, an endless cam carried by said hub, means for operatively connecting the cam and blades wherebythe pitch of the blades will be changed when the cam is rotated relatively to the hub, means for retarding rotation of the cam while the hub continues rotating to eiect relative rotation therebetween, and means for limiting the amount of relative rotation between the cam and hub whereby the pitch of the blades will be varied in predetermined increments.

9. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, and means including a single brake mechanism operable in the same direction for both increasing and decreasing the pitch of the blades..

10. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, -a'member having an inclined plane operatively connected to said blades, and a single brake mechanism for operating said member to both increase and decrease the pitch of the blades.

11. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, an endless cam carried by said hub, means for operatively connecting the cam and. blades, and a single brake mechanism for effecting rotation of the cam relatively to the vhub to both increase and decrease the` pitch of the blades.

12. A propeller comprising a driving shaft, a hub on said shaft, a plurality of blades rotatably carried by said hub, an endless cam carried by said hub, means for operatively connecting the cam and blades, a single brake mechanism for eiiecting rotation of the cam relatively to the hub to both increase and decrease the pitch of the blades,l and means for limiting the amount of relative movement between said cam and hub whereby the pitch of the blades will `be varied in predetermined increments.

13. In a variable pitch propeller having mechanism for changing the pitch of the blades in predetermined increments, control means compr'ising an operating member each movement of which is adapted to vary the pitch of the blades a predetermined amount, and an indicator associated with said operating member for indicating the pitch of the blades. y

14. In a variable pitch propeller having mechanism for changing the pitch of the blades in predetermined increments, control means comprising an operating member each movement of the hub, means connecting the cam and blades which is adapted to vary the pitch of the blades a predetermined amount, and an indicator connected to the operating member and movable thereby for indicating the pitch of the blades.

15. In a variable pitch propeller having-means including a single brake mechanism for both increasing and decreasing the pitch of the blades in predetermined increments, a lever for operating said brake mechanism, and an indicator movable by said lever during its brake applying movement for indicating the pitch of the blades.

16. A propeller comprising a driving shaft, a hub on the shaft, a plurality of blades rotatably carried by the hub, an endless cam carried by' to rotate the blades in the hub to change the pitch thereof when the cam is rotated relatively to the hub, a single brake mechanism for operating the cam to both increase and decrease the pitch of the blades, an operating member for said brake mechanism and an indicator associated with said operating member to indicate the pitch of the blades.

17. A propeller comprising a driving shaft, a hub on the shaft, a plurality of blades rotatably carried by said hub, an endless c carried by the hub, means connecting the cam and blades to effect pitch-changing rotation of the blades when the cam is rotated relatively to the hub, brake mechanism for retarding rotation of the cam to effect relative movement between the cam and hub, means for limiting relative movement between the cam and hubduring a given operation whereby the pitch of the blades will be varied in predetermined increments, an operating member for the brake mechanism, and an indicator cooperating with said operating member for indicating the pitch of the blades.

18. In a variable pitch propeller having a hub and a plurality of blades carried thereby, an endless cam, means connecting said cam and blades to eiect pitch-changing movement of the blades when the cam is moved relatively thereto, a brake mechanism, means connecting said cam. and mechanism and operable in one direction to cause relative movement between the cam and blades when said brake mechanism is operated, and means for moving said last-named means in the opposite direction without moving said cam.

19. In a variable pitch propeller having a hub and a plurality of blades carried thereby, an endless cam having ratchet teeth thereon, means connecting said cam and blades to eiiect pitchchanging movement of the blades when the cam is moved relatively thereto, a brake mechanism, pawls carried by said brake mechanism and cooperating with said ratchet lteeth to move said cam relatively to said blades in one direction when the brake mechanism is operated, means for limiting movement of said pawls, and resilient means for moving said pawls in the opposite direction when the brake mec is released.

l C. ROTH. 

